Amazon has the Microsoft 3500 Wireless Mobile Mouse (Cyan) for $9.99 with free shipping on $25+ or with Prime. List price: $30. Features one AA battery provides up to 8 months of battery life. Has good Amazon Reviews.
Amazon has the Anker Ergonomic 5-Button Wireless Vertical Mouse (Black, AK-98ANWVM-UBA) for $17 - $3 off with coupon ANKER7852 = $14 with free shipping on $25+ or with Prime. List price: $20. Scientific ergonomic design encourages healthy neutral "handshake" wrist and arm positions for smoother movement and less overall strain. Has good Amazon Reviews.